This invention relates to novel escharase containing proteolytic enzyme products, therapeutically useful compositions containing such materials, and to methods of utilizing such products especially in debridement of eschar tissue.
Considerable efforts have been made to discover materials capable of distinguishing between viable and non-viable tissue. The discovery of materials which would digest devitalized tissue while not attacking viable tissue would make it possible to remove the devitalized tissue without surgery. It would be a beneficial therapeutic agent in virtually all disease processes where topically devitalized tissue needs to be removed from the viable organism such as decubitus ulcers, pressure necroses, incisional traumatic and pyogenic wounds, and ulcers secondary to peripheral vascular disease.
One area that has attracted considerable attention is the use of proteolytic enzymes and other chemicals to effect the early debridement of eschar tissues resulting from burns. Such devitalized tissue is an excellent culture medium and the principal source of the septicemia which is the proximate cause of death in the majority of severely burned patients. Intensive investigations with such agents as tannic acid, salicylic acid, and pyruvic acid as well as papain, pinguinain, trypsin, streptokinase and other enzymes have not led to satisfactory results. Chemical agents such as tannic acid were found to cause further injury to already damaged tissue. Known proteolytic enzymes were found to be too slow, to have toxic side effects or to attach viable as well as devitalized tissue.
It is important that debridement of eschar tissue take place early, i.e. in a period which is preferably no longer than four days, and by an agent which effects debridement rapidly. If debridement is postponed for too extentive a period, there results septicemia from invasion of the wound by infectious microorganisms and toxemia from absorption by viable tissue of toxic degradation products from the devitalized tissue. Rapid debridement is essential since the environment normally utilized is one which serves as an ideal culture media for the growth of infectious colonies of microorganisms.
As a result, sharp, surgical debridement with its attendant pain and heavy bleeding continues to be the principal method for the removal of eschar.
The enzyme bromelain which is, in fact, a complex mixture containing materials including a number of hydrolytic and proteolytic enzymes has been used in the treatment of burns. In fact, hydrated bromelain powder and some crude extracts of bromelain have been employed previously for debridement of eschar tissue; see Journal of the Maine Medical Association, September 1964; Research in Burns, Han Huber, Publishers Bern Stuttgart Vienna 1971. These materials, however, have now proved to be satisfactory, principally because the results were not reproducible.